Muffler



C. BALOUGH Feb. 16, 1932.

MUFFLER Filed Dec. 5, 1929 attomcq Patented Feb. 16, 1932 UNiTEi) STATESPATENT OFFICE CHARLES BALOUGH, OF CANTON, OHIO, ASSIGNOB TO HERCULESMOTORS CORPORATION, OF CANTON, OH O, A CORPORATION OF OHIO 'MIUFFLERApplication filed December 3, 1929.

My invention relates to mufilers more particularly for use on theexhaust ducts of internal combustion engines.

An efficient mufiier should not only eliminate the noise otherwisecaused by the relatively large stream of exhaust gas at relatively highpressure expanding directly into the atmosphere and producing reportslike a series of gun shots, but the muffler must also eliminate thisobjectionable noise without causing any substantial loss of power in theengine by producing back pressure.

For these purposes a muffler should offer minimum resistance to thepassage of the exhaust gases, and the velocity and pressure of theexhaust gases should be reduced so that the gases will expand to nearlyatmospheric pressure before they are discharged into the air.

For attaining the foregoing necessary results, mufflers of usual designhave included a relatively large number of parts such as bafilcs,intercommunicating chambers, and the like, and have occupied arelatively large space.

Particularly in connection with internal combustion engines used forindustrial power, it is becoming increasingly necessary to make all theparts of the engine as compact as possible, in order that all of theessential parts and accessories now required for efficient engineoperation may be included in the total space allotted for the engine aswhole.

Accordingly the objects of the present invention include the provisionof an efficient muiller of simplified and economical construction, andthe muffler as whole being very compact and occupying a relatively smallspace.

These objects are attained in the present invention, as is hereinafterdescribed and claimed.

A preferred embodiment of the invention is illustrated in theaccompanying drawings forming part hereof, in which Figure 1 is afragmentary side elevation view of the improved muffler hereof, withportions illustrated in section as on line 1-1,

Fig.2;and I c Serial No. 411,303.

tube, preferably passes through the center of curvature of the segmentalshell 13.

At the base of the segmental shell 13, an annular flange 14 extendsoutwardl from the periphery thereof preferably at right angles to theaxis Y-Y, and a deflector sleeve flange 15 extends from the outerperiphery of the annular flange 14 in the direction towards which theconcave face 13?) of the segmental shell 13 opens.

A dome shell or member 16, the concave face 16?) of which opens towardsthe concave face 13?) of the se mental shell 13, includes an annularbase flange 17 extending outwardly from the base periphery of the domeshell 16 preferably parallel with the annular flange 14 of the segmentalshell 13.

As shown in the drawings, the maximum distance between each of theconcave faces 13b and 16b and the common plane of the bases of the domeshells 13 and 16 respectively, is preferably less than the radius ofcurvature of the respective faces.

Preferably integral with the base flange 17, circumferentially spacedfeet 18 are secured to the dome shell 16 and each includes a a base 19parallel with the flange 17, but spaced therefrom in the direction ofthe segmental shell 13.

The diameter of the flange 17 is substantially less than the innerdiameter of the sleeve flange 15, whereby the dome shell 16 may beseated with the feet bases 19 abutting against the flange 14, therebyforming a pluralityof side opening arcuate slots 20 between the spacedflanges 14 and 17 and the the inner'face a of the deflector sleeveflange 15.

The tube 11 preferably terminates within the dome chamber 23 formed bythe segmental shell 13 and the dome shell 16, and

preferably in the plane of the annular flange .14 of the segmental shell13.

The shells are secured to each other by any suitable fastening meanssuch as rivets 24 which pass through registering apertures in thefeet-bases 19 and the flange ll.

The walls of the shells 13 and 16 thus form a domed chamber 23 whichreceives exhaust gas through the inlet tube 11 and the opposite concaveinner faces of the shells reduce the velocity of the incoming gas andchange the direction of its flow first by the impact of the molecules ofthe gas with the inner concave face 16?) of the dome shell 16, and thenby deflection therefrom to impact with the inner concave face 137) ofthe segmental shell 13 and subesquent deflections back and forth betweenthe concave faces.

The velocity of the exhaust gas entering the mufiier is largely in thedirection YY, consequently the tendency of any unit quantity of exhaustgas entering the chamber 23 is to be deflected first between the concavefaces of the shells and then to move laterally of the axis Y-Y towardsthe side opening slots 20. By the time any unit quantity of gas hasreached the side opening slots, its velocity and pressure has beenreduced substantially to atmospheric pressure by impact and deflectionbetween the concave shell faces.

The slots 20, being relatively long arcuately, and relatively narrow inthe direction of the Y axis, do not permit the-escape of any gas havinga substantial velocity component in the direction of the Y axis; but theslots 20 provide large outlet openings for gas, the velocity andpressure of which has been re duced substantially to the desiredmagnitudes.

The gas emitted through the arcuate slots 20 is again deflected by thesleeve flange 15 and this flnal deflection of the gas passing throughthe improved muffler 10 serves to absorb any remaining pressure orvelocity energy in the gas of suflicient magnitude to make a sound uponsudden expansion to atmospheric pressure, and also "prevents gasstriking the face of a person standing near the mufller.

While the structure of the improved muffler 10 is exceedingly simple andvery compact as illustrated, it is very eiiicient for absorbing thevelocity and high pressure energy in the exhaust gases by impact andbombardment between the concave shell faces, and at the same time themuffler 10 has a large capacity by reason of the relatively long andnumerous arcuate outlet slots 20.

As illustrated, the segmental shell 13 and the dome shell 16, and theparts connected respectively therewith, are each made from integrallyformed sheet or strip metal.

Thus forming the shells of sheet metal, not only decreases theproduction cost thereof, but it has been found that the operation of theimproved muffler when formed of sheet metal parts, is superior to theoperation of the same structure when made of cast and lfiClllIlQClparts.

The sheet metal shells, being much thinner than the equivalent cast andmachined shells, absorb by tleir own resilience, the energy lost by thebombardment of the exhaust gases on the inner concave faces of thechamber 23.

Each of these shells act as diaphragms which are. vibrated by the impactof the exhaust gas thereagainst, but the frequency of the vibration ofthe shells is not usually within audible range.

Moreover, the relatively thin sheet metal shells act as superior heattransfer walls for transferring to the atmosphere any heat generated inthe material of the shell by the bombardment of the exhaust gases.

The mufflers 10 when in use on internal combustion engines arefrequently exposed to the atmosphere, and moisture from rain, fog, snow,or the like may enter the muffling chamber 23 through the annular space22 and the slots 20. 1 7

Suitable draining apertures 25 are formed in the normally lowersegmental shell 13, preferably adjacent the sleeve 12, whereby any watercollected in the muffler chamber 23 may drain out of the same throughthe apertures 25.

An outwardly extending drip flange 26 is preferably secure-d upon thepipe 11 preferably at the outer end of the sleeve 12 and extendsoutwardly from the pipe over the normally upper end of an engine duct 27into which the pipe 11 extends thereby preventing water from drippingfrom the chamber through the apertures 25 into the engine through theduct 27 by deflecting the water and causing it to flow outwardly overthe outer periphery of the drip flange.

it will be seen that since the inlet tube 11 terminates in the plane ofthe annular flange 14 of the segmental shell 13, that is, adjacent theplane of the slots 20, gases entering the chamber through the inlet aredirected against the concave face 166 to be deflected therefrom withoutfirst permitting sufficient expansion of the gases to allow any portionthereof to escape out through the slots before the velocity of the gaseshas been substantially reduced.

I claim:

1. A mufller including dome shaped walls forming an exhaust gasreceiving chamber, opposite inner faces of the chamber walls beingconcave and having their bases located in a common plane, the maximumdistance between each inner concave face and the plane of the basesbeing less than the radius of curvature of the face, walls forming aninlet duct for directing exhaust gas toward one of the concave faces,and there being a side opening outlet slot formed in the domed chamberwalls, and a wall forming a deflector spaced from and traversing theslot.

2. A mufiier including dome shaped walls forming an exhaust gasreceiving chamber, opposite inner faces of the chamber walls each beingconcave and having their bases located in a common plane, the maximumdistance between each inner concave face and the plane of the basesbeing less than the radius of curvature of the face, walls forming aninlet duct extending into the chamber and terminating substantially atthe plane of the bases for directing exhaust gases toward one of theconcave faces, there being a side opening outlet slot formed in thedomed chamber Walls, and a wall forming a deflector spaced from andtraversing the slot.

3. A mufller including dome shaped walls forming an exhaust gasreceiving chamber, opposite inner faces of the chamber walls each beingconcave and having their bases located in a common plane, the maximumdistance between each inner concave face and the plane of the basesbeing less than the radius of curvature of the face, walls forming aninlet duct extending into the chamber and terminating substantially atthe plane of the bases for directing exhaust gases toward one of theconcave faces, there being a side opening outlet slot formed in the domechamber walls.

4. A mufller includin a pair of domed members secured together at theirbases and forming an exhaust gas receiving chamber having its oppositeinner faces each concave, walls forming an inlet duct for directingexhaust gas toward one of the concave faces, there being side openingoutlet slots formed in one of the domed members at its base, and adeflecting wall formed on the other domed member and spaced from andtraversing the outlet slots.

5. A muffler including a pair of domed members secured together at theirbases and forming an exhaust gas receiving chamber having its oppositeinner faces each concave, walls forming an inlet duct extending into thechamber and terminating substantially at the plane of the jointure ofthe bases for directing exhaust gas toward one of the concave faces,there being side opening outlet slots formed in one of the domed membersat its base, and a deflecting wall formed on the other domed member andspaced from and traversing the outlet slots.

6. A muffler including a pair of domed members secured together at theirbases and forming an exhaust gas receiving chamber having its oppositeinner faces each concave,

walls forming an inlet duct for directing exhaust gas toward one of theconcave faces, the maximum distance between each inner concave face andits base being less than the radius of curvature of the face, therebeing side opening outlet slots formed in one of the domed members atits base, and a deflecting wall formed on the other domed member andspaced from and traversing the outlet slots.

7. A mufHer including a pair of domed members secured together at theirbases and forming an exhaust gas receiving chamber having its oppositeinner faces each concave,

walls formin an inlet duct extendin into the chamber and terminatingsubstantially at the plane of the jointure of the bases for directingexhaust gas toward one of the concave faces, the maximum distancebetween each inner concave face and its base being less than the radiusof curvature of the face, there being side opening outlet slot-s formedin one of the domed members at its base, and a deflecting wall formed011 the other domed member and spaced from and traversing the 9. Amufller including a pair of domed sheet metal members having innerconcave faces oppositely disposed towards each other to form an exhaustgas receiving chamber, an outwardly extending peripheral flange formed.at the base of each of the domed members, one of said flanges havingdepressions formed therein for connection with the other flange, meansfor connecting the depressed portions of the one flange with the otherflange, and an inlet tube secured within one of the domed members andextending into the exhaust gas receiving chamber for directing exhaustgas toward the inner concaved face of the other domed member.

10. A Inuflier' including a pair of domed sheet metal members havinginner concave faces oppositely disposed toward each other to form anexhaust gas receiving chamber,

an outwardly extending peripheral flange formed at the base of each ofthe domed members, one of said flanges having depressions formedthereinfor connection with the other flange, an angular deflecting memberformed upon the other flange means for connecting the depressed portionsof the one flange with the other flange, and an inlet tube securedwithin one or" the domed members and extending into the exhaust gasreceiving cham- 5 her for directing exhaust gas toward the innerconcaved face of the other domed member.

In testimony that I claim the above, I have "hereunto subscribed myname.

CHARLES BALOUGH.

